This invention relates to means for packing, shipping and automated unloading of stacks of box blanks so as to minimize damage to the box blanks.
A box blank typically consists of a piece of precut cardboard which when loaded into a packaging machine is folded and fastened together by glue or otherwise in a predetermined fashion. Automated packaging systems employing such box blanks are widely used in the packaging of commercial and consumer products, such as breakfast cereals and tobacco products. The box blanks are typically shipped from a point of origin in shipping cases containing, for example, 4000 box blanks, arranged in four stacks of 1000 box blanks per stack. Considerable manual effort is required to open a box blank shipping case, remove a stack of box blanks, and insert the stack into a packaging machine. Apart from the labor intensive nature of the existing method for loading box blanks into the packaging machine, a number of problems arise from these activities.
Conventional packaging machines have a hopper area into which a stack of box blanks is loaded by the machine operator. When the stack of box blanks is depleted, the packaging machine must be idled while the operator procures and loads a new stack of box blanks. As loaded in a standard shipping case, box-blank stacks are generally each about twelve inches high. Since an operator cannot typically handle blocks of box blanks greater than a few inches thick at a time, numerous operations are needed to load the packaging machine hopper. Furthermore, as packaging machine speed increases with the advent of newer models, the time needed to load the hopper with box blanks can become a limiting feature on the packaging system productivity.
Previously known shipping cases suffer from a number of drawbacks. Chief among these is that significant clearance must be provided on either side of the box blank stacks contained within a shipping case to permit the packaging machine operator to reach into the box alongside the stacks to remove portions of a stack. Lateral shifting of the box blanks during transit can occur when portions of the box blank stacks shift sideways into the clearance on the side faces of the box blank stacks. As a result of such sideways shifting, the finish on the box blank, including printing or decorative designs, can become marred, thereby producing an unacceptable final product.
Since methods of determining how many box blanks are placed in each stack are generally imprecise, it frequently occurs in previously known shipping cases that some axial movement of the uppermost box blanks in each stack results. Such movement at the box blank stack ends can further exacerbate lateral shifting or interleaving, thereby damaging the end blanks by bending or marring. Such movement also necessitates manual effort to realign the stack before it can be loaded into the packaging machine hopper. Additional downtime and effort may be required to cull out damaged blanks prior to loading the packaging machine.
Alternatively, when damaged box blanks are not sufficiently culled from the stacks loaded into the packaging machine hopper, distorted blanks may result in misfeeding or jamming of the packaging machine. Considerable expense and downtime may be occasioned by the need to interrupt the packaging machine operation to retrieve damaged box blanks.
It is an object of this invention to provide a shipping case, suitable for automated unloading, which restrains axial movement and lateral interleaving of the box blanks at the stack ends during transit of the shipping case from the point of origin to the point of use.
It is another object of this invention to provide a shipping case, suitable for automated unloading, which minimizes lateral shifting of the box blanks into the clearances provided at the sides of the box to aid manual removal, which shifting occurs due to vibrations induced during shipping and handling of the shipping case.
It is a further object of this invention to provide a shipping case inset, suitable for use in an automated shipping case unloading system, wherein the insert has tabs which when inserted in between the stacks of box blanks restrain axial shifting and lateral interleaving of the box blanks at the stack ends and which supports the shipping case to resist case failure.
It yet another object of this invention to provide a shipping case and shipping case insert which facilitate an automated shipping case unloading procedure, so that the stacks of box blanks may be unloaded from the shipping case with a minimum of operator intervention.
It is still another object of this invention to provide an automated system which opens shipping cases containing stacks of box blanks and lifts the stacks out of the shipping case, conveniently presenting such stacks for manual or automated loading into the packaging machine hopper with a minimum of operator intervention.